The present invention relates to a probe employed in an endoscope system and a fluorescent diagnostic system employing the probe.
When tissue of a living body is illuminated with UV light, the tissue is excited and generates fluorescence (autofluorescence). The fluorescence from tissue that is suffering from a lesion such as a tumor has different characteristics from the fluorescence from normal tissue. Concretely, while the fluorescence from normal tissue has larger intensity in green range than that in red range, the difference between intensities in a green range and a red range is relatively small in the fluorescence from tissue suffering from a lesion. A fluorescence diagnostic system that determines the presence or absence of a lesion in tissue of a living body by comparing the intensity in the green range and the intensity in the red range of autofluorescence through the use of the above described characteristics has been developed.
The fluorescence diagnostic system is provided with a probe that illuminates a living body with excitation light and guides light from the living body. The probe consists of a plurality of illumination optical fibers that guide excitation light and a plurality of detection optical fibers that guide fluorescence. The illumination optical fibers and the detection optical fibers are tied as a composite bundle at the distal end side and are separately tied as an illumination bundle consisting of the illumination optical fibers and a detection bundle consisting of the detection optical fibers at the proximal end side. Further, the fluorescence diagnostic system includes an excitation light source that emits illumination light to be incident on the proximal end of the illumination bundle and a detecting unit that is connected with the proximal end of the detection bundle to receive light from a living body.
In general, the probe is drawn through a forceps channel of an endoscope during observation. That is, an operator directs the distal end of the endoscope toward tissue to be examined with jutting the probe from the distal end of the endoscope. Excitation light guided through the illumination bundle emerges from the distal end of the probe toward the tissue. Then, the tissue illuminated by the excitation light generates autofluorescence. This autofluorescence and the excitation light reflected by the surface of the tissue are incident on the distal end of the probe. Detection light incident on the detection bundle is transmitted by the optical fibers of the detection bundle and emerges from the proximal end of the detection bundle to be detected by the detecting unit. The detecting unit displays the intensity in the green range and the intensity in the red range of the detection light on a monitor. The operator judges that the tissue under examination is normal when the difference between the intensities is large and that the tissue under examination is suffering from a lesion when the difference between the intensities is small.
However, according to the above described diagnostic system, since the probe fills one forceps channel of the endoscope, the forceps channel is unavailable during fluorescence diagnosis when the endoscope has one forceps channel.
Further, when the operator judged that the tissue under examination is suffering from a lesion as a result of the fluorescence diagnosis, the operator often treat the tissue with various treatment instruments such as a forceps or a laser probe. However, if the forceps channel is occupied with the probe, the operator must pull out the probe as a first step and then insert a treatment instrument into the forceps channel. Such a replacement requires much expense in time and effort. Further, the direction of the distal end of the endoscope directed to the tissue suffering from a lesion may deviate during the replacement, which requires time to redirect the distal end toward the tissue suffering from a lesion.